GBlist: RE: mold on wood

["Sigi Koko" <sigikoko@earthlink.net>]

Hi Rob,

you from a structural point of view, the black mold is not a sign of
imminent failure.  It is a sign that you have achieved greater than 20%
moisture content in a cellulosic material.  What it also means, is that you
have activated the decomposition process.  This process can only proceed
while you have 20%MC; otherwise everything is dormant.  If you noticed that
the plywood is delaminating, however, I would consider replacement (at least
spot replacement) of those pieces.  Is there some way that you can dry-in
the plywood?

There is one indoor air quality note about the mold, however.....many people
are at least mildly allergic to mold spores.   When the wood dries out, the
mold will die, but is reactivated as soon as it gets wet again.  (In other
words, you kindof always have a dormant colony.)  One thing you can do to
kill the mold, is to wash it out with a mild bleach solution.  Ok, so now
you are introducing chlorine, and that may be bad in a way also, but
chlorine is highly volatile, and should evaporate quickly.

Hope this answers your question.
Sigi Koko

DOWN TO EARTH
Natural Building Design + Construction
Environmental Consulting

703/243-5030
sigikoko@earthlink.net
http://home.earthlink.net/~sigikoko/
1527 N. Stafford Street, Arlington VA  22207

_____________________________

Date: Sat, 30 Dec 2000 20:05:49 -0800
From: "Robert Bolman" <robtb@efn.org>
Subject: GBlist: mold on wood

I was trying to get my earthen floor to dry while at the same time having no
gutters.  The interior of the building was hot and humid while the exterior
was getting wet with rain water.  My plywood sheathing got wet repeatedly
and started to turn moldy.

To what extent to I have to worry that such splotchy, black discoloration
will lead to a dryrot problem.  I consider painting such areas with a borax
solution.

Thanks,
Rob

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